create integration pages for windows and linux (#140)

* create integration pages for windows and linux

* update the Linux and Windows integration pages

* update the Linux and Windows integration pages

Author: DebashisBorgohainO2

docs/images/linux-integration.png

@@ -6,4 +6,7 @@ nav:
     - Database: database
     - Servers: servers
     - DevOps : devops
-    - Application Platform: application-platform
+    - Linux: linux.md 
+    - Windows: windows.md
+    - Application Platform: application-platform
+

docs/images/windows-integration.png

@@ -0,0 +1,208 @@
+---
+title: Linux Monitoring Integration with OpenObserve
+description: Learn how to integrate Linux systems with OpenObserve to collect and analyze system logs and performance metrics using the OpenObserve Collector or OpenTelemetry Collector.
+---
+# Integration with Linux
+
+This guide explains how to integrate Linux systems with OpenObserve to collect and analyze system logs and performance metrics.
+
+## Overview
+
+Linux systems generate two primary types of monitoring data: system logs and performance metrics. Collecting and analyzing these data is essential for maintaining system health, performance, and security.
+
+---
+
+## Installation Options
+
+OpenObserve provides two approaches to monitor Linux systems:
+
+- **OpenObserve Collector**: A simple, one-command installation recommended for most users.
+- **OpenTelemetry Collector**: A flexible option for advanced or customized environments.
+
+---
+
+## Steps to integrate
+
+=== "Using the OpenObserve Collector (Recommended)"
+
+    **Prerequisites**
+
+    - A Linux machine such as Ubuntu, Debian, CentOS, or RHEL
+    - Root or sudo access to install and configure services
+    - Access to an OpenObserve instance, either [cloud](https://openobserve.ai/docs/getting-started/#option-1-openobserve-cloud-setup) or [self-hosted](https://openobserve.ai/docs/getting-started/#option-2-self-hosted-installation)
+
+    **Steps**
+
+    1. Log in to your OpenObserve instance.
+    2. Navigate to **Data Sources** > **Recommended** > **Linux**.
+    3. Copy the provided installation command. The command includes your endpoint and API key. 
+    4. Run the command in your terminal:
+    ```
+    curl -O https://raw.githubusercontent.com/openobserve/agents/main/linux/install.sh && chmod +x install.sh && sudo ./install.sh https://your-openobserve-instance.com/api/default/ YOUR_API_KEY
+    ```
+    ![linux integration](../images/linux-integration.png)
+    
+
+    What the OpenObserve Collector Does:
+
+    - Installs as a systemd service
+    - Collects system logs from journald or syslog
+    - Collects host metrics including CPU, memory, disk, network, and process-level usage
+    - Forwards all collected data to OpenObserve
+
+=== "Using the OpenTelemetry Collector"
+   
+    **Steps** 
+
+    1. Set Up the OpenTelemetry Collector
+    Check for the latest version of the OpenTelemetry Collector on the official [releases page](https://github.com/open-telemetry/opentelemetry-collector-releases/releases).
+    ```bash linenums="1"
+    sudo mkdir -p /opt/otel-collector
+    cd /opt/otel-collector
+    curl -L https://github.com/open-telemetry/opentelemetry-collector-releases/releases/download/v0.115.0/otelcol-contrib_0.115.0_linux_amd64.tar.gz -o otelcol-contrib.tar.gz
+    tar -xzf otelcol-contrib.tar.gz
+    ```
+    2. Configure the OpenTelemetry Collector
+    Create a file named `config.yaml` in the `/opt/otel-collector` directory with the following content: 
+    ```yaml linenums="1"
+    receivers:
+    filelog:
+        include:
+        - /var/log/syslog
+        - /var/log/auth.log
+        - /var/log/kern.log
+        - /var/log/messages
+        - /var/log/secure
+        start_at: end
+        include_file_path: true
+        include_file_name: true
+        operators:
+        - type: regex_parser
+            regex: '^(?P<time>[A-Z][a-z]{2}\s+\d{1,2}\s+\d{2}:\d{2}:\d{2})\s+(?P<host>[^\s]+)\s+(?P<service>[^\s\[]+)(\[(?P<pid>\d+)\])?:\s+(?P<message>.*)$'
+            timestamp:
+            parse_from: time
+            layout: Jan 02 15:04:05
+    
+    hostmetrics:
+        collection_interval: 30s
+        scrapers:
+        cpu:
+            metrics:
+            system.cpu.utilization:
+                enabled: true
+        memory:
+            metrics:
+            system.memory.utilization:
+                enabled: true
+        disk:
+        filesystem:
+        network:
+        load:
+        paging:
+        process:
+            mute_process_name_error: true
+            metrics:
+            process.cpu.utilization:
+                enabled: true
+            process.memory.utilization:
+                enabled: true
+
+    processors:
+    batch:
+        send_batch_size: 1024
+        timeout: 10s
+    resourcedetection:
+        detectors: [system, env]
+        system:
+        hostname_sources: ["os"]
+
+    exporters:
+    otlphttp/openobserve:
+        endpoint: "https://your-openobserve-instance.com/api/default"
+        headers:
+        Authorization: "Basic YOUR_API_KEY"
+        stream-name: "linux-logs"
+    debug:
+        verbosity: detailed
+
+    service:
+    pipelines:
+        logs:
+        receivers: [filelog]
+        processors: [resourcedetection, batch]
+        exporters: [otlphttp/openobserve, debug]
+        metrics:
+        receivers: [hostmetrics]
+        processors: [resourcedetection, batch]
+        exporters: [otlphttp/openobserve, debug]
+    telemetry:
+        logs:
+        level: "info"    
+    ```
+    Replace `https://your-openobserve-instance.com/api/default` with your OpenObserve endpoint and `YOUR_API_KEY` with your actual API key.
+    3. Run the Collector
+
+    ```bash
+    sudo ./otelcol-contrib --config config.yaml
+    ```
+
+---
+
+## Advanced Configuration Options
+Here are some essential configurations to enhance your Linux monitoring:
+
+??? "Security-Focused Monitoring"
+    For enhanced security monitoring:
+    ```bash linenums="1"
+    filelog:
+    include:
+        - /var/log/auth.log
+        - /var/log/secure
+        - /var/log/audit/audit.log
+    operators:
+        # For SSH authentication events
+        - type: router
+        routes:
+            - expr: 'includes(file.name, "auth.log") or includes(file.name, "secure")'
+            output: auth-parser
+        - type: regex_parser
+        id: auth-parser
+        regex: '(?P<time>[A-Z][a-z]{2}\s+\d{1,2}\s+\d{2}:\d{2}:\d{2})\s+(?P<host>[^\s]+)\s+sshd\[(?P<pid>\d+)\]:\s+(?P<message>.*)'
+        timestamp:
+            parse_from: time
+            layout: Jan 02 15:04:05
+    ```
+    This configuration focuses on authentication logs to help detect unauthorized access attempts and potential security breaches.
+
+??? "Using Journald Receiver"
+    If you prefer to collect logs directly from journald instead of log files:
+    ```bash linenums="1"
+    journald:
+    units:
+        - ssh.service
+        - systemd-logind.service
+    priority: info
+    ```
+    The journald receiver requires systemd and only works on Linux systems using systemd as their init system.
+
+## Troubleshooting
+
+??? "OpenObserve Collector Installation Issues"
+    - **Permission Denied**: Run the installation command with `sudo`.
+    - **Service Not Starting**: Check status with `sudo systemctl status openobserve-agent` and look for error messages.
+    - **Network Issues**: Verify connectivity with `curl -v https://your-openobserve-instance.com`.
+
+??? "Log Collection Issues"
+    - **Missing Logs**: Check file permissions and ensure the OpenObserve Collector has read access to log files.
+    - **Journald Access**: For systemd-based systems, ensure the OpenObserve Collector has proper journal access.
+    - **Log Format Problems**: If logs appear malformed, check timezone settings and log formats.
+    
+??? "Metrics Collection Issues"
+    - **Missing Metrics**: Verify the OpenObserve Collector has permissions to access system metrics.
+    - **Performance Impact**: If the OpenObserve Collector uses too many resources, adjust collection intervals.
+
+??? "OpenTelemetry Collector Issues"
+    - **Configuration Errors**: Validate your config.yaml syntax and check OpenTelemetry Collector logs.
+    - **Export Failures**: Verify your endpoint URL and API key are correct.
+    - **Resource Constraints**: Adjust batch settings if the OpenTelemetry Collector terminates unexpectedly.
+